When you type characters into the console, its going to STDIN.
you're wanting to modify the character value coming from the keyboard.
There are Windows API functions available for this. off the top of my head i can't remember what they are. MSDN would be your best bet for this.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...